Why Do Worm Egg Counts?
The way we treat for worms is changing from the historic practices of treating every 8/12 weeks. This is based on the types of worms most prevalent today but may of course change in the future. 20% of horses carry 80% of worm burdens [1] and so it is deemed inappropriate to treat all horses all the time. Last year (2013) I found that 75% of the horses I tested did NOT need worming at the time of sampling.
Worm egg counts are a useful indicator of the presence of adult worms. By selectively treating only those horses that require treating the effectiveness of the wormers available will be prolonged. Overuse and maladministration has lead to resistance in all 3 classes of drugs used to treat redworm and ascarids and this will become more widespread over time. (A bit like antibiotics in humans). Resistance is irreversible and there are no new worming drugs to treat horses coming onto the market anytime soon. It also takes 10 years to develop and bring on to the market drugs suitable for horses.
It may also save some money if your horse is one of the 70-80% that doesn’t need worming. You will however need to worm at least once a year during autumn/winter months with an appropriate wormer(s) which is effective against encysted redworm and tapeworm. A tapeworm treatment can also be done in spring. There is a blood test that can be done to test for tapeworm – performed by the vet.
Youngsters will need worming more often.
References
[1] Kaplan, R.M. and Nielsen, M.K. 2010. An evidence-based approach to equine parasite control: It ain't the 60s anymore. Equine Veterinary Education, 22 (6), 306–316.
The way we treat for worms is changing from the historic practices of treating every 8/12 weeks. This is based on the types of worms most prevalent today but may of course change in the future. 20% of horses carry 80% of worm burdens [1] and so it is deemed inappropriate to treat all horses all the time. Last year (2013) I found that 75% of the horses I tested did NOT need worming at the time of sampling.
Worm egg counts are a useful indicator of the presence of adult worms. By selectively treating only those horses that require treating the effectiveness of the wormers available will be prolonged. Overuse and maladministration has lead to resistance in all 3 classes of drugs used to treat redworm and ascarids and this will become more widespread over time. (A bit like antibiotics in humans). Resistance is irreversible and there are no new worming drugs to treat horses coming onto the market anytime soon. It also takes 10 years to develop and bring on to the market drugs suitable for horses.
It may also save some money if your horse is one of the 70-80% that doesn’t need worming. You will however need to worm at least once a year during autumn/winter months with an appropriate wormer(s) which is effective against encysted redworm and tapeworm. A tapeworm treatment can also be done in spring. There is a blood test that can be done to test for tapeworm – performed by the vet.
Youngsters will need worming more often.
References
[1] Kaplan, R.M. and Nielsen, M.K. 2010. An evidence-based approach to equine parasite control: It ain't the 60s anymore. Equine Veterinary Education, 22 (6), 306–316.
